This invention relates to endotracheal and tracheotomy tubes, hereafter referred to as tracheal tubes, and more particularly to an improved cuff configuration for tracheal tubes.
Tracheal tubes are used to provide an air-way through the trachea into the lungs of a patient during respirator therapy or general anesthesia. Hydraulic cuff tracheal tubes include a liquid-fillable, inflatable cuff surrounding the portion of the tube located in the trachea. During use, the cuff is filled with liquid to inflate the cuff so it seals against the patient's trachea. The hydraulic pressure applied to the cuff for inflation typically is provided by a collapsible liquid-filled reservoir or syringe being held at an elevation above the cuff which allows liquid to flow through a filling lumen and into the cuff. Hydraulic cuff tracheal tubes of this type produce a relatively small amount of pressure against the trachea, and are distinguished from pneumatic cuff tracheal tubes which generally do not have as precise control over the inflation pressure applied to the cuff. As a result, pneumatic cuff tracheal tubes, as well as hydraulic cuff tubes not having precise control over the filling pressure, produce considerable trauma to the patient.
Tracheal tubes are known generally, and are disclosed, for example, in U.S. Pat. Nos. 3,348,542; 3,766,927; and 3,854,484 to Jackson.
One difficulty with prior tracheal tubes is that the cuff in its collapsed condition is very floppy, which obscures visibility to the back of the mouth when the physician places the tube in the patient's trachea.
Another difficulty with prior tracheal tubes is that the cuff, when inflated, can move back and forth in the trachea in response to inhalation and exhalation of the patient, resulting in extreme trauma to the patient. For example, if the cuff, when inflated, is of generally uniform diameter and is relatively large in diameter relative to the tube, then a substantial effective area is provided between the ends of the inflated cuff. This area is sensitive to pressure differentials across the cuff as produced in the trachea during inhalation and exhalation phases of the patient's respiration cycle. These pressure differentials across the ends of the cuff create a "pistoning" effect in the cuff, which can shift the cuff up and down in the trachea, causing trauma to the patient, as well as irritation to the patient's trachea.